<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<style>
    div{
        width: 50px;
        height: 10px;
        margin: 20px auto;
    }
</style>
<body>
    <div class="box-1"></div>
    <div class="box-2"></div>
    <div class="box-3"></div>
    <script>
        let box1 = document.querySelector('.box-1');
        let box2 = document.querySelector('.box-2');
        let box3 = document.querySelector('.box-3');

        //数字累加展示
        let num1 = 0;
        let num2 = 0;
        let num3 = 0;
        let max1 = 121221
        let max2 = 7500
        let max3 = 33
        let speedy = 40
        

        timer1 = setInterval(function(){
            num1 += max1 / speedy;
            box1.innerHTML = Math.round(num1);
            if(num1 >= max1){
                box1.innerHTML = max1;
                clearInterval(timer1);
            }
        }, 50);

        timer2 = setInterval(function(){
            num2 += max2 / speedy;
            box2.innerHTML = Math.round(num2);
            if(num2 >= max2){
                box2.innerHTML = max2;
                clearInterval(timer2);
            }
        }, 50);

        timer3 = setInterval(function(){
            num3 += max3 / speedy;
            box3.innerHTML = Math.round(num3);
            if(num3 >= max3){
                box3.innerHTML = max3;
                clearInterval(timer3);
            }
        }, 50);

        
    </script>
</body>
</html>